In October 2025, the zine tmp.0ut interviewed Doug McIlroy at Dartmouth College during "Binary Fun Week". McIlroy, born in 1932, was present for the creation of Unix and C at Bell Labs and is credited with the quote: "The real hero of programming is the one who writes negative code."

echo was the first C program he ever wrote, around 1972, when C had just been invented. He also added most of the options to sort, originally written by Ken Thompson, after Thompson told him to go put them in the source himself. He wrote tee and tr as well, each in a night.

McIlroy describes Ken Thompson as one of the greatest programming geniuses he has known. Thompson built the first master-rated chess machine, whose architecture was later imitated by Deep Blue at IBM. After Bell Labs management killed Multics, Thompson found a cast-off PDP-7 and built the whole operating system in three weeks while his wife was on vacation: one week for the assembler, one for the operating system, one for the file system.

McIlroy himself invented Unix pipes. He had lobbied for a way to connect programs, and when he came up with a workable shell notation, Thompson implemented it in one night, using two read-write pointers in an already shared buffer. That same night he and Dennis Ritchie adapted a large number of programs to be pipeable. By the end of the week the lab's secretaries were piping output to the line printer. The | symbol itself came later, because Thompson was embarrassed to present the original double-greater-than notation at a talk in London. The exit-status semantics of pipelines, McIlroy admits, happened accidentally.

Other stories: his Lisp compiler written in macros, running at macro call depths of 50 to 70; the speak text-to-speech program he wrote in one night for the Votrax synthesizer from Federal Screw Works, which non-native speakers found easier to understand than real speech thanks to 10-millisecond gaps between words; and the spell checker built as a pipeline with a 30,000-word vocabulary compressed to fit 64K of memory, later featured in Jon Bentley's Programming Pearls.

His favorite bug: a Fortran 2 compiler failure on the IBM 7090 where a computed go-to with exactly 74 branches (74 mod 75) broke because of a misused store tag instruction in a paged 75-word table. He found it after an all-night session at the console, before debuggers existed.

McIlroy also confirms Ken Thompson actually implemented the "trusting trust" compiler backdoor; it nearly escaped when another group copied it from his home directory, but they detected it and Thompson ordered it removed. Separately, Tom Duff's experimental shell virus from around 1987 got loose on the Bell Labs network and was only discovered on McIlroy's and Jim Reeds' IX multi-level secure Unix when its integrity control flagged the infection. Duff had written a disinfectant, but their machine had been disconnected while it ran.

On culture: Bell Labs paid for usefulness to the company, not paper counts, and anyone could walk into an expert's office for help. Multics had a five-foot shelf of design documents and still did not work; Unix's first manual appeared two years after the system. These days McIlroy, who joined Dartmouth in 1997, programs in Haskell for map projections and Christmas cards, and does power series reversion in one line where Knuth needs half a page of pseudocode.